This invention relates to the art of vehicle windshield cleaning systems having a number of selectable modes of operation and, more particularly, to improvements in such systems enabling manual adjustment of operating characteristics in certain of the selectable modes.
Windshield cleaning systems for automotive vehicles comprising electric motor driven wiper blades are of course well known and, in connection therewith, it is likewise well known to provide motor control circuitry including a manually positionable selector component enabling the selection of any one of several different operating modes for the wiper blades. Among such modes, for example, is a mist mode in which the control circuitry operates in response to momentary actuation by the vehicle operator of the selector component to energize the blade drive motor to achieve one cycle of blade oscillation across a vehicle windshield. This mode enables cleaning of the windshield when fog, mist, light rain or other weather or road conditions are not bad enough to require repeated periodic or continuous oscillation of the wiper blades. Such selectable operating modes further include low speed and high speed blade operation modes in which the wiper blades are continuously reciprocated or oscillated and in which modes the drive motor for the wiper blades is respectively energized for low speed and high speed operation. These modes are operator selectable normally in accordance with how the vehicle is operated and the environment in which the vehicle is being operated, such as in medium and heavy rain or snowfall for example and, in these modes, the wiper blades are continuously oscillated until such time as the vehicle operator switches the selector to the off or other selectable mode positions. In more recent years, an additional mode of operation was added to most windshield cleaning systems. This additional mode is referred to as a pulse mode, in which the wiper blades are automatically, intermittently oscillated at low speed through one cycle of displacement across the vehicle windshield with a time delay between succeeding cycles. This mode provides for automatic, intermittent, oscillation of the wiper blades for maintaining the windshield clean in borderline weather and road conditions which, without this mode, would require the operator to periodically, manually activate the mist mode. In the pulse mode, each period of operation has a total duration which is determined by the time required for one oscillating cycle of the wiper blades plus the time of delay before initiation of the succeeding blade oscillating displacement. The pulse mode, like the low and high speed modes, continues once the operator has displaced the mode selector into the appropriate position and activated the switch until the operator deactivates the switch or selects another mode position.
It is also well known to provide a vehicle with a windshield wash system, which may be a separate system, used in association with the windshield cleaning system, or may be integrated into the windshield cleaning system as a windshield wash mode of a multi-mode windshield cleaning system. As a separate system, the windshield wash system may include a reservoir for storing a washing fluid or liquid, a pump means for moving the washing fluid from the reservoir to the windshield and a network of tubing for carrying the wash fluid from the reservoir to the windshield. Separate wash systems may include a manually operated pump, such as a pump operated by a foot depressed pump lever or handle, or may include a powered or driven pump operated by a switch separate from the selector switch of the windshield cleaning system. Actuation of a two part system, i.e. a washer system and a cleaning or wiper system may be two separate functions or operations, done by the vehicle operator. Integration of the washer system into the windshield cleaning system provides a composite system in which the two systems function on a coordinated basis, i.e., the wash mode of the windshield cleaning system.
In the wash mode of the windshield cleaning system the selector switch for selecting the mode of operation, is moved into the wash mode position and actuated, or otherwise actuated in the wash mode position, and a predetermined, fixed quantity of wash fluid is pumped onto the windshield and the wiper blades are oscillated at a predetermined speed continuously through at least several cycles. Oscillation of the blades, in the wash mode, serves to scrub or wipe the windshield on which the cleaning fluid has been dispensed thereby washing the outside surface of the windshield. Depending upon the switch system used, the wiper blades may stop after several cycles thereby completing the wash mode cycle or the wiper blade may continue oscillating until switched off by the operator, thereby completing the wash mode cycle. If the windshield has not been cleaned to the driver's or operator's satisfaction, the wash mode may be repeated, using another such predetermined, fixed quantity of wash fluid.
The various systems described above have disadvantages. The separate systems arrangement has the disadvantage of requiring the vehicle operator to individually operate two separate systems to effect washing of the windshield. A safety hazard is created when operating this system due to driver distraction. The washer system that includes a manually operated pump also creates a safety hazard generated by another type of driver distraction. The automatic dispensing of a fixed quantity of wash fluid creates a safety hazard generated by several factors.
Dirt, as opposed to water from mist, rain or snow, deposited on a windshield, may come from several sources such as, for example, tire spray, road dirt splashing, leaf stains, tree-sap droppping and/or smog or generally dirty air, to name just a few. Thus, dirt accumulation on a windshield may come in a wide variety of ways and degrees of accumulation. Dispensing of a preset or fixed quantity of washer fluid may be insufficient to clean the windshield during one wash mode cycle. An excessively dirty condition may require that the operator activate the wash mode cycle several times, in order to clean the windshield, which is an operator distraction and a safety hazard. Dispensing of a preset or fixed quantity of washer fluid onto a windshield that is not excessively dirty may be using an excessive amount of fluid which is wasteful and is an unwarranted expense especially where specially formulated washer fluids are concerned. The use of a fixed amount dispensing system may also use up the limited quantity of washer fluid in the reservoir which can result in early depletion of the fluid supply in the reservoir which may be hazardous in extended operation of the vehicle under adverse weather and road conditions. Further, since washer fluid may differ, from one supply to the next, i.e., one wash fluid supply in the reservoir may be a formulated mix while the next supply used may be clear water, the use of a fixed dispensing system may be very wasteful, or insufficient to do a proper windshield cleaning operation.